In crop harvesters, particularly of the type that is known as cotton strippers, there is a vigorous action within the harvesting housing when the cotton bolls are detached from the plants. The cotton plants move through a plant passage in the housing. Often the action is so vigorous that cotton bolls are thrown out or discharged out of the front end of the passage. In order to prevent loss of cotton in this manner it has been conventional in the past to provide chains that depend from their upper ends connected to the housing which hang in the mouth of the passage. The lower or free ends are, of course, free to move in all directions. This has met with some success because as cotton bolls are thrown forwardly by the harvesting mechanism they may strike some of the depending chains and fall back into the harvesting mechanism. However, such an arrangement has not met with great success since the chains will tend to deform in accordance to the plants that are moving throughh the passage. Also, in some instances the chains will knock off loose cotton bolls before they are permitted to enter into the passage thereby causing them to be lost onto the ground.